Thermal Radiation Heat Transfer Effects on Single Fuel Droplet Heat up Considering it's Internal Circulation

High temperatures are often encountered in almost all of the combustion systems, therefore, thermal radiation heat transfer can influence the droplets heat up rate and consequently their life time. In this paper, the effect of thermal radiation heat transfer is investigated for two cases of directional and spherically symmetric illuminations. The flow and temperature fields insdie and outside of the droplet are solved numerically using control volume approach in the presence of thermal radiation. Mie theory is used for the case of directionally illuminated droplet and Dombrovsky’s simplified model is employed for the spherically symmetric illumination to determine the amount and distribution of the absorbed thermal heat inside the droplet. Maximum absorption for a dodecane droplet occurs at the back of the droplet when subjected to directional illumination, while it happens on the surface of the droplet for spherically symmetric illumination. Results show that the heat up rate is less affected by directional radiation whereas spherically symmetric radiation enhances the heat up rate.